CMOS - Complimentary Metal Oxide Semiconductor -

CMOS non-volatile static RAM (SRAM) is used to store the configuration
information for a computer system. It stores hardware information like
drive type, memory size, floppy type(s), etc. The system battery is

CMOS Memory Size Mismatch will occur whenever the memory size is
changed. This simply indicates that the memory size is different than
the value stored in CMOS. To clear this error, turn on or reboot the
system and go into CMOS setup. DO NOT make any changes. Simply exit
and save CMOS values. This will rewrite the CMOS values, including
the new memory size.

In older AMIBIOS dated 1990 and before, extended CMOS settings can
be reset to default values by holding down the INSert key when the system
is powered up.